"And I understand that as a Catholic, not a particularly good Catholic, that that is an important sacrament within my church.

"But I struggle to understand that if a priest confesses to another priest that he has been involved in paedophile activities, that that information should not be brought to police."

Cardinal Pell said priests should avoid hearing confession from colleagues suspected of committing child sex abuse to avoid being bound by the Seal of Confession.

"That would be my advice, and I would never hear the confession of a priest who is suspected of such a thing," he said.

Cardinal Pell also said he hoped to front the royal commission as it would be an opportunity to vindicate the church.

"It's an opportunity to clear the air, to separate fact from fiction," he said.

"We are not interested in denying the extent of misdoing in the Catholic Church, we object to it being exaggerated," he said.

"We object to being described as the only cab on the rank, we acknowledge, with shame, the extent of the problem and I want to assure you that we have been serious in attempting to eradicate it and deal with it...

"This commission will enable those claims to be validated or found to be a significant exaggeration."

Cardinal Pell would not be drawn on whether personal allegations made against him as far back as 1996 influenced his current perceptions on the issue.

"I am sensitive to the justice to every person involved," he said.

"They have a right to justice."

He later added that he believed "cynicism" over the church's willingness to address abuse claims was limited to "elements of the press (and) elements of the public".

He also questioned whether the NSW police force was adequately resourced to deal with abuse claims.

Cardinal Pell said he understood why senior police officer Peter Fox had spoken out about child sex abuse but he didn't believe his claims of a church cover-up were true.

"I don't think there is sufficient evidence for him to say because of the particular problems that he faced at this time or that time, that the church is covering up. Because we're not."